I've been using Y! Go 2.0 on my Curve 8300 for a few weeks. Tonight I fired it up for the first time since upgrading my OS a few days ago. It would NOT cooperate. I had to select my country again - which I did - and then it clunked along on the next step, telling me it was configuring, and then downloading, and after a few mins it aborted with an error msg telling me to exit and load it again.

I repeated this half a dozen times, and if FINALLY worked.

My point - don't give up. I'm guessing it's not an issue with Y! Go and the 8320 so much as it may be a provisioning problem from Yahoo...